Clinical Focus

  • Vitreoretinal Surgery
  • Retinal Electrophysiology
  • Retinal Degeneration
  • Age Related Macular Degeneration
  • Retina Specialist

Academic Appointments

  • Clinical Assistant Professor, Ophthalmology

Boards, Advisory Committees, Professional Organizations

  • Fellow, American Society of Retinal Specialists (2014 - Present)
  • Member, American Academy of Ophthalmology (2012 - Present)

Professional Education

  • Fellowship: Stanford University Ophthalmology Fellowships (2010) CA
  • Residency: Columbia University Medical Center Ophthalmology (2009) NY
  • Board Certification: American Board of Ophthalmology, Ophthalmology (2010)
  • Internship: St Vincent's Catholic Medical Center Manhattan (2006) NY
  • Medical Education: Johns Hopkins University School of Medicine (2005) MD
  • Fellowship, Stanford University- Ophthalmology Department, Vitreoretinal Diseases and Surgery (2012)

All Publications

  • METformin for the MINimization of Geographic Atrophy Progression (METforMIN): A Randomized Trial. Ophthalmology science Shen, L. L., Keenan, J. D., Chahal, N., Taha, A. T., Saroya, J., Ma, C. J., Sun, M., Yang, D., Psaras, C., Callander, J., Flaxel, C., Fawzi, A. A., Schlesinger, T. K., Wong, R. W., Bryan Leung, L. S., Eaton, A. M., Steinle, N. C., Telander, D. G., Afshar, A. R., Neuwelt, M. D., Lim, J. I., Yiu, G. C., Stewart, J. M. 2024; 4 (3): 100440


    Metformin use has been associated with a decreased risk of age-related macular degeneration (AMD) progression in observational studies. We aimed to evaluate the efficacy of oral metformin for slowing geographic atrophy (GA) progression.Parallel-group, multicenter, randomized phase II clinical trial.Participants aged ≥ 55 years without diabetes who had GA from atrophic AMD in ≥ 1 eye.We enrolled participants across 12 clinical centers and randomized participants in a 1:1 ratio to receive oral metformin (2000 mg daily) or observation for 18 months. Fundus autofluorescence imaging was obtained at baseline and every 6 months.The primary efficacy endpoint was the annualized enlargement rate of the square root-transformed GA area. Secondary endpoints included best-corrected visual acuity (BCVA) and low luminance visual acuity (LLVA) at each visit.Of 66 enrolled participants, 34 (57 eyes) were randomized to the observation group and 32 (53 eyes) were randomized to the treatment group. The median follow-up duration was 13.9 and 12.6 months in the observation and metformin groups, respectively. The mean ± standard error annualized enlargement rate of square root transformed GA area was 0.35 ± 0.04 mm/year in the observation group and 0.42 ± 0.04 mm/year in the treatment group (risk difference = 0.07 mm/year, 95% confidence interval = -0.05 to 0.18 mm/year; P = 0.26). The mean ± standard error decline in BCVA was 4.8 ± 1.7 letters/year in the observation group and 3.4 ± 1.1 letters/year in the treatment group (P = 0.56). The mean ± standard error decline in LLVA was 7.3 ± 2.5 letters/year in the observation group and 0.8 ± 2.2 letters/year in the treatment group (P = 0.06). Fourteen participants in the metformin group experienced nonserious adverse events related to metformin, with gastrointestinal side effects as the most common. No serious adverse events were attributed to metformin.The results of this trial as conducted do not support oral metformin having effects on reducing the progression of GA. Additional placebo-controlled trials are needed to explore the role of metformin for AMD, especially for earlier stages of the disease.Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

    View details for DOI 10.1016/j.xops.2023.100440

    View details for PubMedID 38284098

    View details for PubMedCentralID PMC10810745

  • Crystalline Hepatopathy Associated With Bietti Crystalline Dystrophy: A Striking Manifestation of Disordered Fatty Acid Metabolism. The American journal of surgical pathology Dulken, B. W., Bahceci, D., Leung, L. S., Mahajan, V. B., Choi, W. T., Tan, S. Y. 2024


    Bietti crystalline dystrophy (BCD) is a rare heritable retinal disease characterized by crystal deposition primarily in the retina. It is associated with atrophy of the retinal pigment epithelium (RPE) and is caused by variants in CYP4V2, which encodes a cytochrome P450 hemethiolate protein superfamily member. CYP4V2 is involved in the selective hydrolysis of saturated medium chain fatty acids, and patients with BCD demonstrate abnormalities in fatty acid metabolism, including abnormal lipid profiles and the accumulation of the pathogenic crystals within the RPE, which leads to the visual pathologies characteristic of BCD. However, the precise identity of the crystals is currently unknown, and BCD has no established extraocular manifestations. Here, we report granulomatous hepatitis associated with abundant diffuse crystalline clefts in the hepatic parenchyma in 3 patients with retinal dystrophy and dyslipidemia: 2 with pathogenic CYP4V2 variants and 1 patient with clinical ophthalmologic findings suggestive of BCD but without available genetic testing. The unique and striking histologic features unifying the liver biopsies in all 3 patients strongly support a process related to abnormal fatty acid metabolism underlying the genetic disease of BCD, expanding the spectrum of BCD and shedding light on the importance of CYP4V2 in systemic fatty acid metabolism.

    View details for DOI 10.1097/PAS.0000000000002253

    View details for PubMedID 38802997

  • METformin FOR the MINimization (METforMIN) of Geographic Atrophy Progression in Patients with Non-exudative Age-Related Macular Degeneration - A Randomized Trial Shen, L., Keenan, J., Chahal, N., Taha, A., Saroya, J., Ma, C., Sun, H., Yang, D., Flaxel, C., Fawzi, A., Schlesinger, T., Wong, R., Leung, L., Eaton, A., Yiu, G., Stewart, J. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2023
  • Incidence and associations of retinal detachment after Yttrium Aluminum Garnet (YAG) capsulotomy Cheng, B., Hwang, B., Leung, L. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2023
  • Patterns of Diagnostic Imaging for Stroke after Retinal Artery Occlusion Hwang, B., Cheng, B. T., Leung, L. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2023
  • Severe progression of pentosan maculopathy over a decade. American journal of ophthalmology case reports Guo, L. Y., Mishra, K., Leung, L. B. 2023; 30: 101826

    View details for DOI 10.1016/j.ajoc.2023.101826

    View details for PubMedID 36941944

    View details for PubMedCentralID PMC10023981

  • Electroretinographic findings in retinal vasculitis. The British journal of ophthalmology Ghoraba, H. H., Matsumiya, W., Or, C., Khojasteh, H., Patel, P., Karaca, I., Regenold, J., Zaidi, M., Hwang, J., Lajevardi, S., Yavari, N., Than, N. T., Park, S. W., Akhavanrezayat, A., Uludag, G., Yasar, C., Leung, L. B., Nguyen, Q. D. 2022


    To describe and correlate electroretinographic responses with clinical and angiographic findings in retinal vasculitis (RV).Medical records of patients with diagnosis of RV at a tertiary eye centre from December 2017 to May 2021 were reviewed. Cases in which fluorescein angiography (FFA) and full field electroretinography (ffERG) were done within 1 month were included. FFAs were graded according to the Angiography Scoring for Uveitis Working Group from 0 to 40, where 0 is normal. A novel ffERG grading system was implemented where individual waves were graded for timing and amplitude and general ffERG score was determined with 6 being a perfect score.20 patients (34 eyes) were included. Mean age was 43.9±19.8 years; 70% were female. Median best-corrected visual acuity was 0.8 (0.08-1). Mean FFA score was 12.6±6.5. Median general ffERG score was 5 (0-6). 68% and 91% of eyes had responses with general ffERG scores ≥5 and 4, respectively. Flicker timing was most commonly affected.FFA scores weakly correlated with delayed photopic cone b-wave and flicker timing (p=0.03 and 0.016, respectively). Vitreous haze moderately correlated with delayed cone b-wave timing (p<0.001), delayed flicker timing (p=0.002) and weakly correlated with lower flicker amplitude (p=0.03). Underlying systemic disease was associated with poor ffERG responses.In this study, RV was not frequently associated with severe global retinal dysfunction Higher FFA scores, and vitreous haze grading were weakly, but significantly, correlated with cone-generated ffERG responses.

    View details for DOI 10.1136/bjo-2022-321716

    View details for PubMedID 36130816

  • C3 glomerulopathy associated with both hypertensive retinopathy and purtscher-like retinopathy. American journal of ophthalmology case reports Zaidi, M., Mishra, K., Nguyen, H. V., Miller, P. P., Ghoraba, H., Karaca, I., Matsumiya, W., Nguyen, Q. D., Leung, L. B. 2022; 27: 101683


    Purpose: This article reports the case of a 21-year-old woman with both hypertensive retinopathy and Purtscher-like retinopathy in association with C3 glomerulopathy.Observations: The patient was referred for bilateral painless vision loss with posterior pole cotton wool spots, optic disc edema, and confluent retinal whitening suggesting a mixed picture of hypertensive retinopathy, with initial blood pressure 236/152, and Purtscher-like retinopathy. She was subsequently diagnosed with C3 glomerulopathy which likely caused her severe hypertension and which likely occurred alongside Purtscher-like retinopathy due to a shared pathogenesis of complement dysregulation. Follow up examination and imaging revealed gradual improvement in visual acuity, almost complete resolution of fundus exam abnormalities, improvement in macular nonperfusion, resolution of disc leakage and choroidal leakage, resolution of macular edema, and residual outer retinal hyperreflective foci in both eyes.Conclusion and importance: This case represents the first report of both Purtscher-like retinopathy and hypertensive retinopathy occurring in association with C3 glomerulopathy. It supports investigation of anti-complement therapy as a potential treatment for Purtscher-like retinopathy.

    View details for DOI 10.1016/j.ajoc.2022.101683

    View details for PubMedID 36016724

  • Immunotherapy-induced retinopathy mimicking cancer associated retinopathy. American journal of ophthalmology case reports Ghoraba, H., Or, C., Karaca, I., Mishra, K., Akhavanrezayat, A., Park, S., Than, N., Leung, L., Sanislo, S., Dong Nguyen, Q. 2022; 26: 101449


    Purpose: To report a patient who developed a cancer associated retinopathy (CAR) like syndrome in the setting of pembrolizumab and lenvatinib combination therapy for metastatic endometrial carcinoma. Symptoms resolved with normalization of objective functional tests following cessation of medications.Observations: A 52-year-old female with history of endometrial carcinoma, managed with pembrolizumab infusions and daily oral lenvatinib treatment for 18 months, presented to a tertiary eye center with complaints of nyctalopia, photosensitivity and photopsia. Further investigations revealed a reduction in b-wave amplitude on full field ERG (ffERG), a mild color vision deficit, and positive antiretinal antibodies against carbonic anhydrase II, enolase and arrestin. A preliminary diagnosis of CAR was made. One month following diagnosis, the patient discontinued both lenvatinib and pembrolizumab and subsequently reported significant improvement in her eye symptoms and vision. Repeat ffERG had normalized with a robust b-wave, with an improvement noted on repeat color vision testing. A presumed diagnosis of immunotherapy-induced retinopathy was made, with clinical findings mimicking CAR.Conclusions and importance: Pembrolizumab and lenvatinib treatment may be associated with a reversible retinopathy, with presentation very similar to CAR.

    View details for DOI 10.1016/j.ajoc.2022.101449

    View details for PubMedID 35265774

  • Electroretinographic findings in retinal vasculitis Ghoraba, H., Matsumiya, W., Patel, P., Or, C., Karaca, I., Regenold, J., Zaidi, M., Khojasteh, H., Hwang, J., Lajevardi, S., Yavari, N., Park, S., Akhavanrezayat, A., Mobasserian, A., Nguyen, Q. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2022
  • Macular Edema and Serous Macular Detachment after a Standard Dose of Intracameral Cefuroxime OPHTHALMIC SURGERY LASERS & IMAGING RETINA Davila, J. R., Mishra, K., Leung, L. 2021; 52 (11): 615-618


    Intracameral cefuroxime has been associated with postoperative macular edema and sub-retinal fluid. To date, nearly all published cases are attributed to errors in antibiotic dilution, leading to administration of supratherapeutic doses. We report three cases of postoperative macular edema and subretinal fluid following a standard dose of 1 mg/0.1 mL of cefuroxime at the end of cataract surgery. Distinguishing features of these cases were intraoperative zonular instability and history of vitrectomy. We hypothesize that certain factors may increase the risk of cefuroxime-associated retinal toxicity, including history of vitrectomy, zonular compromise, posterior capsular break, surgery for a secondary intraocular lens, and unicameral state. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:615-618.].

    View details for DOI 10.3928/23258160-20211027-01

    View details for Web of Science ID 000732807000006

    View details for PubMedID 34766852

  • Comparison of Telemedicine Screening of Diabetic Retinopathy by Mydriatic Smartphone-Based vs Nonmydriatic Tabletop Camera-Based Fundus Imaging. Journal of vitreoretinal diseases Han, Y. S., Pathipati, M., Pan, C., Leung, L., Blumenkranz, M. S., Myung, D., Toy, B. C. 2021; 5 (3): 199-207


    Purpose: To compare dilated smartphone-based imaging with a nonmydriatic, tabletop fundus camera as a teleophthalmology screening tool for diabetic retinopathy (DR).Methods: This was a single-institutional, cross-sectional, comparative-instrument study. Fifty-six patients at a safety-net hospital underwent teleophthalmology screening for DR using standard, nonmydriatic fundus photography with a tabletop camera (Nidek NM-1000) and dilated fundus photography using a smartphone camera with lens adapter (Paxos Scope, Verana Health). Masked graders performed standardized photo grading. Quantitative comparisons were performed employing descriptive, kappa, Bland-Altman, and receiver operating characteristic analyses.Results: Posterior segment photography was of sufficient quality to grade in 89% of mydriatic smartphone-imaged eyes and in 86% of nonmydriatic tabletop camera-imaged eyes (P = .03). Using the tabletop camera as the reference to detect moderate nonproliferative DR or worse (referral-warranted DR), mydriatic smartphone-acquired photographs were found to be 82% sensitive and 96% specific. Dilated smartphone imaging detected referral-warranted DR in 3 eyes whose tabletop camera imaging did not demonstrate referral-warranted DR. Secondary masked review of medical records for the discordances in referral-warranted status from the two imaging modalities was performed, and it revealed revised sensitivity and specificity values of 95% and 98%, respectively. Overall, there was good agreement between tabletop camera and smartphone-acquired photo grades (kappa = 0.91 ± 0.1, P < .001; area under the receiver operating characteristic curve = 0.99, 95% CI, 0.98-1.00).Conclusions: Mydriatic smartphone-based imaging resulted in fewer ungradable photos compared to nonmydriatic table-top camera imaging and detected more patients with referral-warranted DR. Our study supports the use of mydriatic smartphone teleophthalmology as an alternative method to screen for DR.

    View details for DOI 10.1177/2474126420958304

    View details for PubMedID 34632255

  • Retinal Diseases that Can Masquerade as Neurological Causes of Vision Loss. Current neurology and neuroscience reports Padungkiatsagul, T., Leung, L., Moss, H. E. 2020; 20 (11): 51


    PURPOSE OF REVIEW: This review aims to discuss retinal diseases that may masquerade as neurological causes of vision loss and highlights modern ophthalmic ancillary testing that can help to establish these diagnoses.RECENT FINDINGS: Retinal diseases with signs and symptoms overlapping with neurological causes of vision loss include central serous chorioretinopathy, retinal ischemia, acute macular neuroretinopathy, Acute zonal occult outer retinopathy (AZOOR) complex diseases, paraneoplastic retinopathy, retinal dystrophy, and toxic retinopathy. Diagnosis is facilitated by electrophysiologic studies and multimodal ophthalmic imaging including optical coherence tomography and fundus autofluorescence imaging. Looking into the future, translation of adaptive optics ophthalmoscopy into clinical practice may facilitate early detection of microscopic retinal abnormalities that characterize these conditions. With conventional methods of physical examination, diagnosis of retinal diseases that may masquerade as neurological causes of vision loss can be challenging. Current advance in multimodal ophthalmic imaging along with electrophysiologic studies enhances the provider's ability to make early diagnosis and monitor progression of these conditions.

    View details for DOI 10.1007/s11910-020-01071-1

    View details for PubMedID 32930896

  • Assessment of Eye Disease and Visual Impairment in the Nursing Home Population Using Mobile Health Technology OPHTHALMIC SURGERY LASERS & IMAGING RETINA Lai, K. Y., Pathipati, M. P., Blumenkranz, M. S., Leung, L., Moshfeghi, D. M., Toy, B. C., Myung, D. 2020; 51 (5): 262–70


    To characterize the burden of eye disease and the utility of teleophthalmology in nursing home patients, a population with ophthalmic needs not commensurate with care received.Informed consent was obtained from 78 California Bay Area skilled nursing facility patients. Near visual acuity (VA) and anterior/posterior segment photographs were taken with a smartphone-based VA app and ophthalmic camera system. The Nursing Home Vision-Targeted Health-Related Quality of Life questionnaire was also administered. Risk factors for visual impairment were assessed. Institutional review board approval was obtained from Stanford University.Cataracts (51%), diabetic retinopathy (DR) (12%), optic neuropathy (12%), and age-related macular degeneration (AMD) (10%) were common findings; 11.7% had other referral-warranted findings. AMD and DR correlated with a higher risk of poor VA, with adjusted odds ratios of 22 (P = .01) and 43 (P = .004).This study demonstrated a high prevalence of poor VA and ophthalmic disease in the nursing home population impacting quality of life. Smartphone-based teleophthalmology platforms have the potential to increase access to eye care for nursing home patients. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:262-270.].

    View details for DOI 10.3928/23258160-20200501-03

    View details for Web of Science ID 000539315500003

    View details for PubMedID 32511729

  • Reductions in final visual acuity occur even within the first 3 days after a macula-off retinal detachment BRITISH JOURNAL OF OPHTHALMOLOGY Greven, M. A., Leng, T., Silva, R., Leung, L., Karth, P. A., Moshfeghi, D. M., Sanislo, S. R., Schachar, I. H. 2019; 103 (10): 161–64
  • Reductions in final visual acuity occur even within the first 3 days after a macula-off retinal detachment. The British journal of ophthalmology Greven, M. A., Leng, T., Silva, R. A., Leung, L. B., Karth, P. A., Moshfeghi, D. M., Sanislo, S. R., Schachar, I. H. 2018


    PURPOSE: To determine if final visual acuity (VA) is affected by duration of macular detachment (DMD) within the first week of macula-off retinal detachment (RD).METHODS: This is a retrospective study of eyes that underwent repair within 7 days with vitrectomy or vitrectomy with scleral buckle for macula-off RD at Stanford University Hospital between 1 May 2007 and 1 May 2017. A generalised linear model was constructed using DMD, postoperative lens status, preoperative VA, patient age and surgeon as the independent variables and the final VA as the dependent variable. The main outcome measure was the final VA.RESULTS: Seventy-nine eyes met the entry criteria. Group 1 included 52 eyes with RD repaired within 3 days of DMD, and group 2 included 27 eyes repaired between 4 and 7 days of DMD. The average final VA in group 1 eyes was logarithm of the minimum angle of resolution (logMAR) 0.21 (Snellen 20/33) and in group 2 eyes was logMAR 0.54 (Snellen 20/69). In group 1 and group 2 eyes, preoperative VA (p=0.017and p=0.007), DMD (p=0.004 and p=0.041) and final lens status (p<0.0001and p<0.001) predicted postoperative VA. Post-hoc analysis showed significant differences in final VA between detachments of 1day vs 3 days (p=0.0009).CONCLUSION: DMD affects the final VA even among patients whose DMD is <3 days. Based on these results, interventions that shorten DMD, including those occurring within the first 3days, may result in improved long-term VA outcomes.

    View details for PubMedID 30504489

  • Progressive Reductions in Acuity Occur even within the First Three Days After a Macula-Off Retinal Detachment Greven, M., Leng, T., Leung, L., Moshfeghi, D. M., Sanislo, S., Silva, R., Schachar, I. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2018
  • Photodynamic Therapy-Induced Macular Hole OPHTHALMIC SURGERY LASERS & IMAGING RETINA Greven, M. A., Leung, L. B. 2018; 49 (4): 270–72


    A 72-year-old female with neovascular macular degeneration refractory to anti-vascular endothelial growth factor injections underwent photodynamic therapy and subsequently developed a macular hole (MH) associated with vitreomacular traction. After a period of observation, the MH enlarged. Pars plana vitrectomy was performed, and the MH was closed successfully. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:270-272.].

    View details for DOI 10.3928/23258160-20180329-10

    View details for Web of Science ID 000430534800010

    View details for PubMedID 29664985

  • Comparison of Pneumatic Retinopexy and Scleral Buckle for Primary Rhegmatogenous Retinal Detachment Repair OPHTHALMIC SURGERY LASERS & IMAGING RETINA Paulus, Y. M., Leung, L., Pilyugina, S., Blumenkranz, M. S. 2017; 48 (11): 887–93


    To compare pneumatic retinopexy (PR) and scleral buckle for the repair of primary rhegmatogenous retinal detachment.Retrospective analysis of 90 patients undergoing surgery for primary rhegmatogenous retinal detachment, with 46 patients undergoing PR compared with 44 patients undergoing scleral buckle procedure (SBP).Both groups had similar baseline characteristics. Single surgery reattachment rate was 95.5% with SBP and 67% with PR (P = .00057). Final reattachment rate was 100% with SBP and 97.8% with PR. A final visual acuity (VA) of 20/40 or better occurred in 89% of patients with SBP and 72% of patients with PR (P = .04). PR and SBP had a similar mean VA if the primary procedures were successful, whereas those patients with unsuccessful PR had lower mean final acuities.This study demonstrates that SBP has a significantly higher rate of single surgery reattachment than PR, along with improved final VA. Initial success of PR may be an important predictor of final visual outcome. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:887-893.].

    View details for DOI 10.3928/23258160-20171030-03

    View details for Web of Science ID 000418012200003

    View details for PubMedID 29121357

  • Rapid Onset of Retinal Toxicity From High-Dose Hydroxychloroquine Given for Cancer Therapy. American journal of ophthalmology Leung, L. B., Neal, J. W., Wakelee, H. A., Sequist, L. V., Marmor, M. F. 2015; 160 (4): 799-805 e1


    To report rapid onset of retinal toxicity in a series of patients followed on high-dose (1000 mg daily) hydroxychloroquine during an oncologic clinical trial studying hydroxychloroquine with erlotinib for non-small cell lung cancer.Retrospective observational case series.Ophthalmic surveillance was performed on patients in a multicenter clinical trial testing high-dose (1000 mg daily) hydroxychloroquine for advanced non-small cell lung cancer. The US Food & Drug Administration-recommended screening protocol included only visual acuity testing, dilated fundus examination, Amsler grid testing, and color vision testing. In patients seen at Stanford, additional sensitive screening procedures were added at the discretion of the retinal physician: high-resolution spectral-domain optical coherence tomography (OCT), fundus autofluorescence (FAF) imaging, Humphrey visual field (HVF) testing, and multifocal electroretinography (mfERG).Out of the 7 patients having exposure of at least 6 months, 2 developed retinal toxicity (at 11 and 17 months of exposure). Damage was identified by OCT imaging, mfERG testing, and, in 1 case, visual field testing. Fundus autofluorescence imaging remained normal. Neither patient had symptomatic visual acuity loss.These cases show that high doses of hydroxychloroquine can initiate the development of retinal toxicity within 1-2 years. Although synergy with erlotinib is theoretically possible, there are no prior reports of erlotinib-associated retinal toxicity despite over a decade of use in oncology. These results also suggest that sensitive retinal screening tests should be added to ongoing and future clinical trials involving high-dose hydroxychloroquine to improve safety monitoring and preservation of vision.

    View details for DOI 10.1016/j.ajo.2015.07.012

    View details for PubMedID 26189086

  • Rapid Onset of Retinal Toxicity From High-Dose Hydroxychloroquine Given for Cancer Therapy. American journal of ophthalmology Leung, L. B., Neal, J. W., Wakelee, H. A., Sequist, L. V., Marmor, M. F. 2015; 160 (4): 799-805 e1

    View details for DOI 10.1016/j.ajo.2015.07.012

    View details for PubMedID 26189086

  • Restoration of Retinal Structure and Function after Selective Photocoagulation JOURNAL OF NEUROSCIENCE Sher, A., Jones, B. W., Huie, P., Paulus, Y. M., Lavinsky, D., Leung, L. S., Nomoto, H., Beier, C., Marc, R. E., Palanker, D. 2013; 33 (16): 6800-6808


    CNS neurons change their connectivity to accommodate a changing environment, form memories, or respond to injury. Plasticity in the adult mammalian retina after injury or disease was thought to be limited to restructuring resulting in abnormal retinal anatomy and function. Here we report that neurons in the mammalian retina change their connectivity and restore normal retinal anatomy and function after injury. Patches of photoreceptors in the rabbit retina were destroyed by selective laser photocoagulation, leaving retinal inner neurons (bipolar, amacrine, horizontal, ganglion cells) intact. Photoreceptors located outside of the damaged zone migrated to make new functional connections with deafferented bipolar cells located inside the lesion. The new connections restored ON and OFF responses in deafferented ganglion cells. This finding extends the previously perceived limits of restorative plasticity in the adult retina and allows for new approaches to retinal laser therapy free of current detrimental side effects such as scotomata and scarring.

    View details for DOI 10.1523/JNEUROSCI.1044-12.2013

    View details for Web of Science ID 000317723000012

    View details for PubMedID 23595739



    To evaluate the effect of intravitreal triamcinolone acetonide (TA) on healing of retinal photocoagulation lesions using drug and laser dosing typically employed in clinical practice.Laser burns with a 267-μm retinal beam size at 532-nm wavelength were applied to 40 eyes of Dutch belted rabbits. Barely visible to intense lesions were produced with pulses of 5, 10, 20, and 50 milliseconds and power of 175 mW. Eyes received intravitreal injections of either 2 mg TA/50 μL or balanced salt solution administered either 1 week before or immediately after laser treatment. Lesion grades were assessed acutely ophthalmoscopically and by a masked observer histologically at 1, 3, 7, 30, and 60 days.Both TA groups demonstrated significant reduction in retinal thickness throughout follow-up compared with balanced salt solution groups (P < 0.001). The width of the lesions at 1 day after injection was not significantly different between groups. However, by 7 days, the lesions in balanced salt solution groups contracted much more than in the TA groups, especially the more intense burns, and this difference persisted to 2 months. The healing rate of the barely visible burns was not significantly affected by TA compared with the balanced salt solution control eyes.Triamcinolone acetonide injection previously or concurrently with photocoagulation significantly decreases laser-induced edema but interferes with lesions healing, thereby leaving wider residual scarring, especially persistent in more intense burns.

    View details for DOI 10.1097/IAE.0b013e318261e34b

    View details for Web of Science ID 000313422500008

    View details for PubMedID 23026846

  • Therapeutic Window of Retinal Photocoagulation With Green (532-nm) and Yellow (577-nm) Lasers Annual Meeting of the Association-for-Research-in-Vision-and-Ophthalmology (ARVO) Sramek, C. K., Leung, L. B., Paulus, Y. M., Palanker, D. V. SLACK INC. 2012: 341–47


    The 577-nm (yellow) laser provides an alternative to the 532-nm (green) laser in retinal photocoagulation, with potential benefits in macular treatment and through ocular opacities. To assess relative risk of thermomechanical rupture of Bruch's membrane with yellow laser in photocoagulation, the therapeutic window, the ratio of threshold powers for mild coagulation and rupture, was measured.Retinal coagulation and rupture thresholds, visualized ophthalmoscopically, were measured with 577- and 532-nm lasers using 10- to 100-ms pulses in 34 rabbit eyes. Lesions at 1 and 7 days were assessed histologically.Coagulation threshold with yellow laser was 26% lower than with green laser. The therapeutic window increased linearly with log-duration for both wavelengths with a difference in parallel-slope intercept of 0.36 ± 0.20, corresponding to 8% to 15% wider therapeutic window for yellow wavelength.The therapeutic window of retinal photocoagulation in rabbits at 577 nm is slightly wider than at 532 nm, whereas histologically the lesions are similar.

    View details for DOI 10.3928/15428877-20120426-05

    View details for Web of Science ID 000312366000012

    View details for PubMedID 22589338

  • Macular infarction following intravitreal bevacizumab for treatment of central retinal vein occlusion. Ophthalmic surgery, lasers & imaging : the official journal of the International Society for Imaging in the Eye Leung, L. B., Silva, R. A., Blumenkranz, M. S., Flynn, H. W., Sanislo, S. R. 2012; 43: e73-9


    Bevacizumab, a monoclonal antibody against vascular endothelial growth factor (VEGF), is widely used for the treatment of macular edema associated with central retinal vein occlusion (CRVO). The authors present a series of three patients with CRVO who suffered apparent macular infarction within weeks of intravitreal administration of bevacizumab. Of the nearly 200 patients undergoing intravitreal injections of bevacizumab for this indication over a surveillance period of 3 years, this event occurred in three patients. This has not been described in the natural history of the disease and is associated with poor visual outcomes.

    View details for DOI 10.3928/15428877-20120712-05

    View details for PubMedID 22823029

  • Non-damaging Retinal Phototherapy: Dynamic Range of Heat Shock Protein Expression INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE Sramek, C., Mackanos, M., Spitler, R., Leung, L., Nomoto, H., Contag, C. H., Palanker, D. 2011; 52 (3): 1780-1787


    Subthreshold retinal phototherapy demonstrated clinical efficacy for the treatment of diabetic macular edema without visible signs of retinal damage. To assess the range of cellular responses to sublethal hyperthermia, expression of the gene encoding a 70 kDa heat shock protein (HSP70) was evaluated after laser irradiation using a transgenic reporter mouse.One hundred millisecond, 532 nm laser exposures with 400 μm beam diameter were applied to the retina surrounding the optic nerve in 32 mice. Transcription from the HSP70 promoter was assessed relative to the control eye using a bioluminescence assay at 7 hours after laser application. The retinal pigmented epithelium (RPE) viability threshold was determined with a fluorescence assay. A computational model was developed to estimate temperature and the extent of cell damage.A significant increase in HSP70 transcription was found at exposures over 20 mW, half the threshold power for RPE cell death. Computational modeling estimated peak temperature T = 49°C at HSP70 expression threshold. At RPE viability threshold, T = 57°C. Similar temperatures and damage indices were calculated for clinical subvisible retinal treatment parameters.Beneficial effects of laser therapy have been previously shown to extend beyond those resulting from destruction of tissue. One hundred millisecond laser exposures at approximately half the threshold power of RPE damage induced transcription of HSP70, an indication of cellular response to sublethal thermal stress. A computational model of retinal hyperthermia can guide further optimization of laser parameters for nondamaging phototherapy.

    View details for DOI 10.1167/iovs.10-5917

    View details for Web of Science ID 000288965300070

    View details for PubMedID 21087969

  • SELECTIVE RETINAL THERAPY WITH MICROSECOND EXPOSURES USING A CONTINUOUS LINE SCANNING LASER RETINA-THE JOURNAL OF RETINAL AND VITREOUS DISEASES Paulus, Y. M., Jain, A., Nomoto, H., Sramek, C., Gariano, R. F., Andersen, D., Schuele, G., Leung, L., Leng, T., Palanker, D. 2011; 31 (2): 380-388


    To evaluate the safety, selectivity, and healing of retinal lesions created using a continuous line scanning laser.A 532-nm Nd:YAG laser (PASCAL) with retinal beam diameters of 40 μm and 66 μm was applied to 60 eyes of 30 Dutch-belted rabbits. Retinal exposure duration varied from 15 μs to 60 μs. Lesions were acutely assessed by ophthalmoscopy and fluorescein angiography. Retinal pigment epithelial (RPE) flatmounts were evaluated with live-dead fluorescent assay. Histological analysis was performed at 7 time points from 1 hour to 2 months.The ratios of the threshold of rupture and of ophthalmoscopic visibility to fluorescein angiography visibility (measures of safety and selectivity) increased with decreasing duration and beam diameter. Fluorescein angiography and live-dead fluorescent assay yielded similar thresholds of RPE damage. Above the ophthalmoscopic visibility threshold, histology showed focal RPE damage and photoreceptor loss at 1 day, without inner retinal effects. By 1 week, photoreceptor and RPE continuity was restored. By 1 month, photoreceptors appeared normal.: Retinal therapy with a fast scanning continuous laser achieves selective targeting of the RPE and, at higher power, of the photoreceptors without permanent scarring or inner retinal damage. Continuous scanning laser can treat large retinal areas within standard eye fixation time.

    View details for DOI 10.1097/IAE.0b013e3181e76da6

    View details for Web of Science ID 000286586500024

    View details for PubMedID 20930656

  • Improving the therapeutic window of retinal photocoagulation by spatial and temporal modulation of the laser beam JOURNAL OF BIOMEDICAL OPTICS Sramek, C., Leung, L., Leng, T., Brown, J., Paulus, Y. M., Schuele, G., Palanker, D. 2011; 16 (2)


    Decreasing the pulse duration helps confine damage, shorten treatment time, and minimize pain during retinal photocoagulation. However, the safe therapeutic window (TW), the ratio of threshold powers for thermomechanical rupture of Bruch's membrane and mild coagulation, also decreases with shorter exposures. Two potential approaches toward increasing TW are investigated: (a) decreasing the central irradiance of the laser beam and (b) temporally modulating the pulse. An annular beam with adjustable central irradiance was created by coupling a 532-nm laser into a 200-μm core multimode optical fiber at a 4-7 deg angle to normal incidence. Pulse shapes were optimized using a computational model, and a waveform generator was used to drive a PASCAL photocoagulator (532 nm), producing modulated laser pulses. Acute thresholds for mild coagulation and rupture were measured in Dutch-Belted rabbit in vivo with an annular beam (154-163 μm retinal diameter) and modulated pulse (132 μm, uniform irradiance "flat-top" beam) with 2-50 ms pulse durations. Thresholds with conventional constant-power pulse and a flat-top beam were also determined. Both annular beam and modulated pulse provided a 28% increase in TW at 10-ms duration, affording the same TW as 20-ms pulses with conventional parameters.

    View details for DOI 10.1117/1.3542045

    View details for Web of Science ID 000288939200056

    View details for PubMedID 21361711

  • Critical appraisal of the clinical utility of the dexamethasone intravitreal implant (Ozurdex) for the treatment of macular edema related to branch retinal vein occlusion or central retinal vein occlusion. Clinical ophthalmology (Auckland, N.Z.) Chan, A., Leung, L., Blumenkranz, M. S. 2011; 5: 1043-1049


    Macular edema is a common cause of visual loss in patients with retinal vein occlusions. Ozurdex(®), a dexamethasone intravitreal implant, has been shown in randomized controlled trials to reduce macular edema and improve visual acuity in patients with either branch retinal vein occlusions or central retinal vein occlusions. It was approved in the United States in 2009. Since then, new therapeutic agents and clinical data have emerged. The purpose of this review is to critically evaluate the clinical utility of Ozurdex(®) in the current treatment strategy of macular edema related to retinal vein occlusion.

    View details for DOI 10.2147/OPTH.S13775

    View details for PubMedID 21845032

    View details for PubMedCentralID PMC3151568

  • Adult Orbital Langerhans Cell Histiocytosis With Frontal Bone Involvement OPHTHALMIC PLASTIC AND RECONSTRUCTIVE SURGERY Sokol, J. A., Kazim, M., Kelly, K. A., Lantos, G., Leung, L., Baron, E. 2009; 25 (2): 157-158


    A 28-year-old woman presented with a 2-week history of right upper eyelid swelling and intermittent frontal headaches. CT demonstrated an ill-defined superior right orbital mass with adjacent right frontal bone erosion and undeveloped frontal sinuses. The orbital biopsy revealed tissue strongly positive for CD1a and S100, diagnostic of Langerhans cell histiocytosis. The systemic workup was negative for multifocal lesions and for diabetes insipidus. In addition to subtotal resection, the patient was treated with a 6-month course of oral prednisone and intravenous vinblastine.

    View details for DOI 10.1097/IOP.0b013e31819ac2d9

    View details for Web of Science ID 000264585400028

    View details for PubMedID 19300172

  • Recent trends in the management of rhegmatogenous retinal detachment SURVEY OF OPHTHALMOLOGY Sodhi, A., Leung, L., Do, D. V., Gower, E. W., Schein, O. D., Handa, J. T. 2008; 53 (1): 50-67


    It has been nearly a century since Jules Gonin performed the first intervention for rhegmatogenous retinal detachment, trans-scleral cautery, achieving successful outcomes in close to 50% of his cases. With the introduction of alternative surgical approaches in the last half-century, including Charles Schepens' scleral buckle technique and Robert Machemer's pars plana vitrectomy, the surgical success rates have risen to close to 90%. Nonetheless, despite dramatic progress in the success of reattachment surgeries, reasonable disagreement exists as to which approach (or combination of approaches) is the best form of surgical intervention for patients with rhegmatogenous retinal detachments. In this review, the authors summarize the current knowledge of retinal detachment, and examine emerging results from the first large scale, prospective, randomized, controlled clinical trials addressing the efficacy of these surgical approaches for retinal detachment, with the hope of identifying the most appropriate (evidence-based) therapeutic intervention for the treatment of rhegmatogenous retinal detachment.

    View details for DOI 10.1016/j.survophthal.2007.10.007

    View details for Web of Science ID 000252538400005

    View details for PubMedID 18191657

  • A novel mutation in intron 11 of the COL2A1 gene in a patient with Type 1 Stickler syndrome RETINA-THE JOURNAL OF RETINAL AND VITREOUS DISEASES Leung, L., Hyland, J. C., Young, A., Goldberg, M. F., Handa, J. T. 2006; 26 (1): 106-109

    View details for Web of Science ID 000234788800019

    View details for PubMedID 16395149